1. Field of the Invention
This invention relates to an improvement in an illumination-type pushbutton switch construction suitable for use in, for example, a terminal device of an electronic computer, a controlling board of a machine tool, a slot machine and the like.
More particularly, the present invention relates to an improved illumination-type pushbutton switch construction which is capable of ensuring the connection between a light emitting element having pin-like terminals disposed in a housing and a socket for securely inserting therein the pin-like terminals to prevent the pin-like terminals from being disconnected from the socket, to thereby accomplish the reliable operation; always keeping the distance between the illumination surface of the switch construction and the light emitting surface of the light emitting element constant irrespective of the state of a pushbutton to accomplish a stable illumination without any attenuation of light; allowing the pushbutton, the light emitting element and a switch actuating means for operating the switch to be easily replaced separate from one another, to thereby facilitate repairs and the like; effectively preventing the switch actuating means from being dislocated from the housing; and always keeping the distance between the illumination surface of the switch construction and the light emitting surface of the light emitting element constant even after the components have been replaced, to thereby accomplish a stable illumination without any attenuation of light.
2. Description of the Prior Art
Conventionally, there have been used two kinds of illumination-type switch constructions, one using an electric lamp having a screw cap and the other using an electric lamp which is lighted by flowing a current to a peripheral metal sheet thereof and the projected portion of a bottom thereof. However, the former switch construction has a disadvantage that the engagement between the screwed portion of the lamp and the switch is loosened due to vibration or the like to cause a contact failure, to thereby decrease reliability in operation, whereas, the latter switch construction has a disadvantage that the lamp is easily disconnected from a C-shaped socket due to vibration or impact.
In such conventional illumination-type switch construction, an illumination unit is generally fixed in a housing of the switch so that it may not move in the housing, as disclosed in Japanese Utility Model Application Laying-Open Publication No. 109225/1980. However, such structure causes a disadvantage that the distance between the illumination surface of the switch and the light emitting surface of a light emitting element is varied dependent on the position of a pushbutton to cause an attenuation of light, thus, it cannot accomplish a stable illumination.
In addition, in view of the durability and life of a switch section and/or in order to facilitate the incorporation of a pushbutton and the replacement of a light emitting element, a switch construction has been proposed which is constructed in such a manner that a switch section and an illumination section are fomred separate from each other. However, such conventional switch construction has a disadvantage that it is substantially impossible to smoothly and easily carry out the replacement of an illumination unit and an operation section including the pushbutton, a switch actuating means and the like.
Another switch construction of such type has been proposed which is constructed in such a manner to form the outer surface of a switch actuating means with guide pawls and engage the guide pawls with openings formed at the opposite side walls of a housing, to thereby prevent the switch actuating means from being dislocated from the housing. However, such conventional switch construction has a disadvantage that moisture, dust and the like enter into the housing through the openings of the housing, to thereby cause failure of the switch construction.
Further, each of the conventional switch constructions mentioned above has a disadvantage that it is highly difficult to replace the pushbutton and the switch actuating means when it is required to positionally change the light emitting element, for example, from the central portion of the pushbutton to the position deflected therefrom as desired.